[En-Nut-Discussion] Time needed to get packet from RTL on ATmega128

[Harald Kipp]

Hi Dusan,

Not sure, what you are looking for.

The code below may indeed produce '@' on the debug
output.

(*ifn->if_recv)(dev, nb) is non-deterministic. With UDP
it ends up at NutEventPost(&sock->so_rx_rdy) in
udpin.c, where any higher priority thread may take over.

May be you can be more precisely about the actual problem
you are hunting.

Harald

At 12:22 07.01.2005 +0100, you wrote:
>Hi,
>
>can sb tell me the amount of time (approx. us) CPU spends with reading a 
>packet in dev/nicrtl.c:THREAD(NicRx) with NicGetPacket ? (I would like to 
>know times for ARP /short/, average UDP and full 1514 packet)
>
>I noticed that latest nicrtl driver removed check for serving max 10 
>packets. We added following check (see below) based on tick count (whole 
>time spent processing a packet) and characters '@' really appear in 
>debugging output.
>
>I think it is not necessary to disable RTL ints because NutEventPost 
>signals ni->ni_tx_rdy from NicInterrupt. When NicRx enters NutEventWait it 
>should then proceed without waiting in NutEventWait.
>
>----
>...
> >>      #define MAX_RECEIVING_TIME      100     //ms
> >>      unsigned long end_tick_count;
>
>         while (1) {
>         NutEventWait(&ni->ni_rx_rdy, 0);
>
> >>      end_tick_count = NutGetTickCount() + (MAX_RECEIVING_TIME*2)/125;
>
>         /*
>          * Fetch all packets from the NIC's internal
>          * buffer and pass them to the registered handler.
>          */
>         do {
>
>             nb = NicGetPacket();
>
>             /* The sanity check may fail because the controller is too busy.
>                restart the NIC. */
>             if ((u_short) nb == 0xFFFF) {
>                 NicStart(ifn->if_mac);
>                 ni->ni_rx_size_errors++;
>             } else if (nb) {
>                 ni->ni_rx_packets++;
>                 (*ifn->if_recv) (dev, nb);
>             }
> >>              if ((NutGetTickCount() >= end_tick_count))
> >>                      putchar('@');
>
> >>        } while (nb && (NutGetTickCount() < end_tick_count));
>
>
>Dusan
>
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